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4
votes
3answers
108 views

What influence has the distance of the moon on the height of the tides?

As the Moon recedes from the Earth, are the tides getting taller or shorter? If the Moon is, someday, twice as far from the Earth, how many high tides will be there be each day?
3
votes
0answers
152 views

Nine Planets in the Solar System?

I just discovered that there is a Caltech team1 that suggests that there is "Evidence of a Ninth Planet": The object, which the researchers have nicknamed Planet Nine, has a mass about $10$ times ...
1
vote
0answers
13 views

Fermi estimate for ice nucleation timescale

My friends in a Cryo-EM lab freeze their very samples quickly, a process they call vitrification. The timescale for this process is milliseconds (from wikipedia): The production of amorphous ice ...
0
votes
2answers
64 views

How much energy would it take to take down a 747 using vibrations? [closed]

Background Information: All materials have a resonant frequency, which is the frequency at which they are most easily excited (vibrated). That's how glass is shattered using high-pitched sounds. ...
1
vote
2answers
81 views

How much iron would result of fusing a human body?

While discussing nonsense plots, a friend and I ran into the question of what would happen to a human enclosed perfectly with an enormous amount of energy, Antimatter or fusion level energy. It was a ...
3
votes
2answers
125 views

How much money can I save on gas by losing weight?

I read somewhere that if you carried around a penny in your car, over the lifetime of the car, you would end up paying an extra penny in gas than if you weren't carrying that penny. I was wondering ...
1
vote
2answers
45 views

Can outgassing produce a significant thrust on a space ship?

There are a variety of materials that outgas in the atmosphere, and I imagine they would do so even more in the vacuum of space. I imagine an object in space would experience a small force as ...
2
votes
2answers
73 views

How to calculate drag forces on an object

Previously, I theoretically calculated the velocity of a bb, accelerated by air pressure, when it exits a barrel. In short, I calculated my velocity to be about 150m/s. However, I wanted a more ...
4
votes
3answers
579 views

Can vinyl LPs store audio above 20kHz and can it be played back? [closed]

If, in the future, humans genetically engineered themselves to be able to hear frequencies significantly above 20kHz (say, up to 100kHz), would they find vinyl LPs a viable method of storing and ...
1
vote
2answers
95 views

What temperature is an evaporating cup of water at “room temperature”?

If I put 100 g of water in a cylindrical cup and I know it takes 2 weeks (lets say 1.2 × 106 seconds) at some RH/temp to completely evaporate in my room with a constant temperature, can I ...
0
votes
0answers
63 views

Calculating the theoretical velocity of a projectile

Recently, I made a homemade air powered airsoft gun. I wanted to know how fast it would accelerate out of the barrel, so I tried do do some calculations, but to no avail (keep in mind, I haven't taken ...
67
votes
8answers
7k views

Does quantum mechanics play a role in the brain?

I'm interested in whether the scale of processes that occur in the brain is small enough to be affected by quantum mechanics. For instance, we ignore quantum mechanics when we analyze a game of tennis ...
5
votes
1answer
271 views

How far away from the Sun does space start to be cold?

I assume that if I stood on the sun, I would be hot. I similarly assume that if I stood about 10 feet from the sun, I would still be hot. However, if I stood in space 93 million miles away, I would be ...
3
votes
1answer
36 views

Sound attenuation when holes size less than wavelength

The actual problem is as follows. There is a gap between a transducer and its circular mounting collar that is about half the wavelength of the incoming sound. What I do not want is for the incoming ...
3
votes
2answers
136 views

Can the Arcaboard fly?

Recently, BBC news had a video that claimed to show a "real" hoverboard: As far as I can tell, there are 36 small fans on this device, and it seems to be flying just a few inches off the ground. ...
2
votes
1answer
62 views

How much microgravity is there on ISS due to tidal forces? [closed]

I used the equation for the tidal force: $$ F = \frac{2GMd}{r^3} $$ where $M$ is the mass of the Earth ($5.972 \times 10^{24}$ kg), $d$ is half the length of ISS ($50$ m), $r$ distance from center ...
11
votes
1answer
2k views

Why don't they use springs as an energy source for cell phones?

I know they used springs for clocks way back in the day and now it's all lithium ion batteries. For reference, consider the Iphone that has a battery with a capacity of 5 Watt hours (18,000 joules). ...
0
votes
1answer
92 views

Could the Large Hadron Collider accelerate one kilogram of protons at once?

Is it possible to accelerate a very large number of protons in a particle accelerator as opposed to only a few as is regularly done? What's to keep someone from accidentally dumping too many particles ...
2
votes
0answers
175 views

Could a falling office tower cause the melting of its iron or steel support structure? [closed]

Discussion on META: Questions related to geopolitical events Suppose you have an office tower, weighing around 300,000 metric tons, and has a height of ...
2
votes
1answer
115 views

Spacetime curvature effect on chemistry

Do current chemistry / astrophysics / stellar chemistry calculations include the effects of the curvature of spacetime on chemical reactions? For example, the heat transfer from a point closer to the ...
1
vote
1answer
115 views

What is the sum of the angles of a triangle on Earth orbit?

Gauss went out and measured triangles made up of mountain peaks to show that the angles sum up to 180 degree. However, general relativity leads to non-Euclidian space and I would like to get a better ...
7
votes
2answers
635 views

How many Gs are my clothes experiencing in my washer? [closed]

During a spin cycle I got curious: How many Gs are at play in my simple washing machine? We can assume the drum is 50 cm wide and spins at 1500 rpm.
6
votes
4answers
2k views

Could we launch a missile from a planet with the mass of Jupiter?

If the Earth had the mass of Jupiter, would we be able to launch a space missile ? Is there a formula to calculate how the launch of 1-Kg payload increases with gravity?
3
votes
3answers
181 views

What would be the minimum size of a planet which would allow a human being to walk around without falling out in the open space?

On the Earth you can walk - of course we all know it - in the southern hemisphere without falling out in the open space, and you feel no difference between being at the North Pole or on the Equator. ...
0
votes
4answers
197 views

Force exerted on carseats?

Can anyone explain how force is exerted on car seats during a crash? I am being told in car seat safety forums that $force=mass \times acceleration$. So if a $2000 \;\text{lb}$ vehicle bumps you at ...
8
votes
1answer
253 views

How loud would a sound have to be to be heard around the world?

I'm reading the book Cosmos by Carl Sagan, and in it he states: Striking the Earth's atmosphere, a modest cometary fragment would produce a great radiant fireball and a mighty blast wave, which ...
1
vote
2answers
92 views

How much fuel do I need to send cubesat 1kg from Earth orbit to Moon orbit? [closed]

How much fuel do I need to send cubesat 1kg from Earth orbit to Moon orbit? And how much stages? For i.e. C12H22O11 + KNO3, polyethylene + oxygen or kerosene + oxygen.
2
votes
1answer
75 views

If the Moon had a large piece blown out would it remain tidally locked?

I just saw this video on Sonic Adventure 2 trivia where it's mentioned that part of the Moon was blown up but in later games it's whole. It was explained away as the Moon simply rotating to show the ...
0
votes
0answers
33 views

Is it possible that my 750ml water bottle contains spent fuel from a space shuttle launch

Firstly I live in New Zealand which is very distant from USA which is where the space shuttle was originally launched from. So what is the possibility of molecules from the rocket engines spent ...
0
votes
0answers
83 views

How general relativity shows that gravity decreases as we go inside the Earth [duplicate]

Why is it that gravity decreases as we go deeper inside Earth? Can anyone explain theoretically with reference to general relativity?
2
votes
4answers
350 views

Will this rope break due to the tidal forces or not?

While I was thinking about how tidal forces can make objects float at the surface of a planet orbiting a massive object like a black hole, the fact that any material on the Earth isn't held together ...
0
votes
3answers
98 views

Is it possible to build planet-sized non-spherical structures?

Beyond certain size and density the celestial objects tend to admit a spherical size. I wonder if is there a fundamental mass, density or specific strength related number which when surpassed a non-...
4
votes
2answers
421 views

Does a clock oscillating in a friction-free hole through the center of a planet run slower than a stationary clock on the surface?

Assume a clock is dropped into a friction-free hole through the center of a symmetric, non-rotating planet, far from any other massive object. Clearly, the clock oscillates from one end of the hole to ...
4
votes
3answers
2k views

Are we increasing the gravity of Earth with our population?

I have these questions related to my question title: Do we, other species and things have our own gravity? How much Gs a human have? Are we effecting Earth, nearby moons and planets with our gravity?...
1
vote
1answer
58 views

Am I experiencing any effect from black holes gravitational pull?

So we know that there is a black hole in the middle of the Milky Way. Am I experiencing any effect from the high gravitational pull of the black hole? If no...then why? If yes...then how much?
0
votes
2answers
93 views

What is a simple calculation to figure out how many watts needed to maintain a hot piece of tungsten?

The specific heat of tungsten is $.13 (\text{kJ /(kg K)})$. 1 cubic cm of tungsten is .0193 kg And the melting point of stainless steel is $1900 \deg \text{K}$ conservatively (giving it plenty of ...
1
vote
1answer
42 views

How much carbon dioxide do we actually ingest from a can of coke?

On this most trustworthy page it states that a 355 mL can of coke contains on average about 2.2 grams of carbon dioxide. As far as I know, this carbon dioxide can exist in solution as carbonic acid, ...
0
votes
2answers
85 views

Can a piece of metal have all of its conduction electrons stripped?

Can a piece of metal have all of its conduction electrons stripped? If so, has this been done and for what value?
0
votes
1answer
153 views

What is the potential and kinetic energy of the international space station?

I know it's possible to calculate, but what formulas would I use to be as accurate as possible? I'd like to see how it works for something big and high like that.
2
votes
0answers
44 views

SOHO solar observatory, comet numbers and composition

SOHO discovered its 3,000th comet, cementing its standing as the greatest comet finder of all time. Prior to the 1995 launch of the observatory, commonly known as SOHO, only a dozen or so comets ...
0
votes
2answers
76 views

Do other people's mass count when measuring the attraction of the earth on me? [duplicate]

Suppose that I'm alone on a planet of $M$. From what I learned from school, the gravitation force acting on me is given by $$F=G\frac{mM}{r^2},$$ where $m$ is my mass, $r$ is the distance between me ...
0
votes
4answers
114 views

Does not the mass of those living on the Earth add on to the mass of the Earth or is it too negligible to be cared for?

Source: Earth weighs about 13,170,000,000,000,000,000,000,000 pounds (or 5,974,000,000,000,000,000,000,000 kilograms). Since Earth is too big to be placed on a scale, scientists use mathematics ...
17
votes
7answers
4k views

How big are clouds? [closed]

How big are clouds? When I look up into the sky I have no frame of reference, so I don't know if they are 200 feet or 2 miles across. When I am in a plane looking out at a cloud, I try to use the wing ...
37
votes
4answers
4k views

How far out from the Sun is visible light still sufficient to read a book?

Recent pictures from the New Horizons spacecraft, shown below, seem to indicate that, at Pluto's distance, we are entering a twilight zone, with a distinct lack of colors, although that could be due ...
0
votes
2answers
174 views

Grand Canyon Sound Problem Troubles

Yesterday, I got a question in class, this is the question: If you shout into the Grand Canyon, your voice travels at the speed of sound (340m/s) to the bottom of the canyon and back, and you hear an ...
29
votes
4answers
6k views

How is it possible that the energy needed to stop a train is the same as the (chemical) energy in a pack of chocolate cookies?

Today my friend told me something that blew my mind completely. He said: The energy necessary to stop a train is equal to the energy in a pack of cookies. How is that possible? Is he right? I'm ...
79
votes
6answers
9k views

Does a gun exert enough gravity on the bullet it fired to stop it?

My question is set in the following situation: You have a completely empty universe without boundaries. In this universe is a single gun which holds one bullet. The gun fires the bullet and the ...
0
votes
1answer
56 views

Looking at a falling person (vertically) from 60m to the surface, how much wind effect is going to be felt?

I am trying to work out horizontal ranges for a falling person from height (in 10m steps from 0m to 60m). I have used this site http://www.convertalot.com/ballistic_trajectory_calculator.html to ...
3
votes
1answer
109 views

How many tons of lead is needed to curve space 1 nanometer? [closed]

How many tons of lead is needed to curve space 1 nanometer?
0
votes
0answers
83 views

Can the curvature of space be measured using a swimming pool?

I read somewhere that if the center of mass of two twelve ton elephants was one meter apart then the space they curve would be one nanometer longer. (Though I doubt elephants come that dense) This ...